File:Swiss National Park 131.JPG|thumb|A Pinophyta|conifer forest in the Swiss Alps (Swiss National Park|National Park)
File:Adirondacks in May 2008.jpg|thumb|The Adirondack Mountains of Upstate New York form the southernmost part of the Eastern forest-boreal transition ecoregion.
File:Stara planina suma.jpg|thumb|Mixed deciduous forest in Stara Planina, Serbia
A '''forest''' is a large area of land covered with trees or other woody vegetation.
Hundreds of more precise definitions of forest are used throughout the world, incorporating factors such as tree density, tree height, land use, legal standing and ecological function.
According to the widely-used
United Nations Food and Agriculture Organization definition, forests covered an area of four billion hectares (15 million square miles) or approximately...